feynmann is right

"mathematics does not require the universe to exist for its validity."

many laws of mathematics do not apply to the universe like
for eg: sum of the angles of a triangle is 180 does not apply in the universe as such.

that is why it is said that the work of a mathematician is easier than a physicist because a physicist has to take into account the practicality of his findings in the universe as well as the mathematics involved to prove it.
whereas a mathematician is not bothered if his law applies to the universe or not,it should only be proved on paper.